West Portal/TBM Launch
The West Portal, located between Brokaw Road and I-880 (Newhall Yard) serves as the launching point for the Tunnel Boring Machine (TBM) to dig the five-mile tunnel. The West Portal is located along a construction site that crosses between the City of Santa Clara and City of San José. The West Portal refers to the overall construction site where many support facilities are located as well as the launch shaft where the TBM will begin tunneling.Â
The West Portal serves as the assembly and eventual launching point for the TBM, and accordingly, the area will house many large support structures.
Click to see full image!
Click to see full image!
The West Portal site hosts several important elements:
- During operation, the West Portal itself (also known as the TBM launch shaft), serves as the exit point for excavated soil, which is transported out of the tunnel via a conveyor system. Additionally, the tunnel lining segments are transported into the tunnel by the same conveyor system and installed by the TBM.Â
- The tunnel lining factory and tunnel lining storage facility are where tunnel lining segments will be fabricated and then stored until needed for placement within the tunnel. The fabricated lining segments will be placed in the tunnel as soil is removed, to create a structurally sound tube underground. One ring of the tunnel is comprised of nine individual lining segments that are roughly 40,000 pounds each. On average, up to six rings per day will be installed by the TBM.Â
- The Grout Plant is also integral to the lining of the tunnel. Grout will be used to seal the tunnel lining segments in place as the TBM advances eastward.Â
- The Excavated Materials Bin is where excavated soils from the tunnel will be stored until hauled offsite to be repurposed or disposed.Â
- A noise curtain will be constructed along the west side of the site to reduce noise from construction activities. The contractor will determine the exact length of the curtain to ensure they meet noise mitigation requirements.Â
This information will be updated with additional details on various construction activities at they become available. Please check back periodically for updates.
Construction Activities
VTA will be conducting activities related to preparing the site for tunneling operations, including: Â
- Constructing on-site access points, designated crew parking, and office space. Â
- Excavating the portal and constructing the TBM launch shaft as well as establishing the excavated materials bin.Â
- Constructing and operating the facilities needed to produce and store the tunnel lining. Â
- Assembling the tunnel boring machine (TBM) required to create the tunnel.Â
Planned Work Hours
- Construction activities at the West Portal are expected to occur between 6 AM to 6 PM. Hauling activities will generally occur between 6 AM to 4 PM, including Saturdays. Â
- When activities are occurring that require extended work hours, construction activities will occur between 6 AM and 4 AM, and hauling activities will occur from 6 AM and 4 AM.Â
- Work hours are subject to change.
Tunneling and Alignment
The last step of the early works construction at the West Portal in Newhall Yard, the Tunnel Boring Machine (TBM) will be assembled on site. The launch of the TBM into the West Portal commences the excavation of the single-bore tunnel. This tunnel will contain two independent track ways, one for each direction of train travel. The TBM is a large electrically powered machine, with a cutter-head that rotates to dig through soil and rock. Excavated soil, rocks, and debris are removed through a conveyor system within the TBM machine, creating the underground tunnel while keeping the above ground surface intact.
Click to see full image!
The video demonstrates how TBMs work. Â
Construction Activities
- The TBM will be capable of excavating and building approximately 30 to 40 feet of the tunnel per day. Since the tunnel will be approximately 75 feet underground, there will be no noticeable impacts on the surface during tunneling. Â
- TBM boring speeds vary greatly, depending on the size and length of the tunnel, geological conditions, and other factors.Â
Planned Work Hours
- Tunneling work is expected to occur 24 hours a day, up to 7 days a week, until the full five-mile tunnel is completed. Â
- Work hours are subject to change.
Santa Clara Station
Construction activities for the Santa Clara Station are anticipated to begin in late 2024.
This information will be updated with additional details on various construction activities at they become available. Please check back periodically for updates.Â
Construction Activities
- Construction activities will include Early Works and Major Project Construction activities such as site preparation and development.  Â
Planned Work Hours
- Work hours during major project construction will be provided at a later date.Â
- Work hours are subject to change.
Diridon Station
The Diridon Station area will include Early Works and Major Project Construction such as site development, building demolition, support of excavation (SOE), and adit excavation.
Work at the Diridon Station area is anticipated to begin in the early 2025.
This information will be updated with additional details on various construction activities at they become available. Please check back periodically for updates.
Construction Activities
VTA will be conducting activities related to site development, including:Â
- On-site access points, designated crew parking, staging areas, and office space. 
- Installation of temporary utilities connections to offices.
- Construction of temporary pedestrian pathwayÂ
- Building demolition and hauling materials off site for disposal.Â
Planned Work Hours
- Work hours during major project construction will be provided at a later date.Â
- Work hours are subject to change.
Downtown San José Station
The Downtown San José Station area will include Early Works and Major Project Construction activities such as site development, building demolition, support of excavation (SOE), and adit excavation.Â
Work at the Downtown San José Station area is anticipated to begin in late 2024.
This information will be updated with additional details on various construction activities at they become available. Please check back periodically for updates.
Construction Activities
VTA will be conducting activities related to site development, including:Â
- On-site access points, designated crew parking, staging areas, and office space. Â
- Installation of temporary utilities connections to offices.
- Building demolition and hauling materials off site for disposal.
Planned Work Hours
- Work hours during major project construction will be provided at a later date.Â
- Work hours are subject to change.
28th Street/Little Portugal Station
Construction activities in the 28th Street/Little Portugal Station area will include Early Works and Major Project Construction activities such as site development, building demolition, support of excavation (SOE), and tunneling and adit excavation.  Â
Work at the 28th Street/Little Portugal Station area is anticipated to begin in late 2024.
This information will be updated with additional details on various construction activities at they become available. Please check back periodically for updates.
Construction Activities
VTA will be conducting activities related to site development, including:Â
- On-site access points, designated crew parking, staging areas, and office space. 
- Installation of temporary utilities connections to offices.
- Installation of pedestrian path and crosswalk  Â
- Building demolition and hauling materials off site for disposal.Â
Planned Work Hours
- Work hours during major project construction will be provided at a later date.Â
- Work hours are subject to change.
East Portal
Construction activities at the East Portal will include Early Works and Major Project Construction activities such as site development, building demolition, support of excavation (SOE), and tunneling and adit excavation.  Â
Work at the East Portal is anticipated to begin in the early fall of 2025 and continue through the end of 2030. Â
This information will be updated with additional details on various construction activities at they become available. Please check back periodically for updates.
Construction Activities
VTA will be conducting activities related to site development, including:Â
- Installation of temporary construction fencing and signageÂ
- Establishing track access and conducting site work  Â
- Establishing BART interim operations  Â
- Building demolition hauling materials off site for disposalÂ
Planned Work Hours
- Work hours during major project construction will be provided at a later date.Â
- Work hours are subject to change.
Newhall Yard & Maintenance Facility
Construction activities for the Newhall Yard & Maintenance Facility will begin once tunnel excavation is completed.  Â
This information will be updated with additional details on various construction activities at they become available. Please check back periodically for updates.
Construction Activities
VTA will be conducting activities related to preparing the site for tunneling operations, including:Â
- Constructing on-site access points, designated crew parking, and office space.Â
- Excavating the portal, constructing the TBM launch shaft, and establishing the excavated materials bin.Â
- Constructing and operating the facilities needed to produce and store the tunnel lining.Â
- Assembling the tunnel boring machine (TBM) required to create the tunnel Â
Planned Work Hours
- Work hours during major project construction will be provided at a later date.Â
- Work hours are subject to change.
VTA’s BSVII Project Construction Sequencing and Schedule
Construction of VTA’s BSVII Project can be segmented into three high-level stages: Early Works Construction, Major Project Construction, and systems testing and commissioning. These stages are discussed in more detail below. The Construction Activities and Sequence graphic below illustrates the various construction activities typical in the three described stages and the corresponding schedule leading up to the target passenger service date by 2037.Â
Early Works Construction
Early Works Construction prepares the various project sites for construction and generally includes utility relocations, site preparation, demolition (e.g., building, pavement, and other site features), and soil testing. Such activities are key to ensuring the tunneling and construction of the stations can proceed on schedule.  Â
Early Works Construction to prepare for the Tunnel and Trackwork includes preparing the Tunnel Boring Machine (TBM) launch and exit sites, taking delivery of and assembling the TBM itself, and excavating and connecting any additional facilities to the tunnel. Review the Tunneling section for more details.
Major Project Construction
Major Project Construction includes the excavation of the five-mile tunnel beginning at West Portal just north of I-880 in VTA’s Newhall Yard property, until exiting at East Portal, near Las Plumas Avenue. In addition, the tunnel will be outfitted with tracks and platforms, which will connect to the stations and supporting facilities at street level. At the West Portal, this will include launching the Tunnel Boring Machine (TBM). At the stations, this work includes digging the deep station shafts for the main station buildings and any additional facilities like ventilation and emergency egress. This work also includes mining the underground connections (called adits) between the station shafts and the tunnel. Activities such as digging deep shafts typically need longer working hours, including weekends, because State and Federal safety requirements require they be filled as quickly as possible.  Â
Once the station shafts and the adits have been constructed, the remainder of the station and associated facilities will be constructed. This work includes installation of vertical circulation (e.g., staircases, escalators, and elevators), construction of the aboveground station building, application of architectural finishes, and more.
VTA’s BSVII Contracting
Delivering a megaproject to connect the San Francisco Bay region requires extensive construction and coordination. To maximize efficiencies, BSVII Project construction has been separated into four smaller contract packages (CP) to allow for some portions of construction to advance, while design is still being finalized for other project elements. Contract Packages 1 through 4 are briefly described below in the order they are being implemented.Â
The tunnel and trackwork for the 5-mile-long, single bore tunnel, along with the initial site preparation for each work area will be constructed under Contract Package 2 (CP2). The four stations and maintenance yard will be constructed under Contract Packages 3 (CP3) and 4 (CP4). The key systems required for BART passenger operations (Guideway Systems and Facility Systems) will be constructed under Contract Package 1 (CP1). For additional details on the various construction packages and their activities, please visit the VTA BART Phase II Contracting Page.